This invention relates to a new and useful method of simultaneous mass manufacture of transparent envelope assemblies adaptable for receiving shipping labels or the like. In particular, the present invention concerns manufacturing of adhesive envelopes adaptable for easily fastening documents and the like to sides of shipping containers.
Known envelope assemblies usually require a layer of adhesive on a first envelope surface which folds over and seals an insert therein, and a separate layer of adhesive entirely covering a second envelope surface for attaching the envelope to a shipping container. This results in a complicated envelope assembly which must be separately sealed shut and affixed to the container. In addition, a layer of protective material, such as paper, intially covers the adhesive material to prevent inadvertent adhesion and is peeled away and disposed of immediately prior to attachment of the envelope to the container.
The excessive use of adhesive materials and especially the excessive use of protective paper greatly increases the manufacturing costs without providing any increased operating benefits.
For example, U.S. Pat. No. 3,327,416 issued June 27, 1967 to Sanford suggests a transparent envelope which is attached to a shipping container by means of a plurality of adhesive strips covering more than one-half the envelope surface abutting the container.
U.S. Pat. No. 3,355,090 issued Nov. 28, 1967 to Werby suggests manufacturing a plurality of transparent envelopes one after aother from a strip which can be addressed accordingly. There is no suggestion in Werby of simultaneously manufacturing a plurality of envelopes from an enlarged strip of transparent, two-ply plastic material.
Finally, Finnish Patent Application No. 760,982 also suggests a transparent envelope requiring the entire surface abutting the container to be covered by adhesive, and which is not adaptable to simultaneous, mass manufacture.
As will be described in detail hereinafter, the present invention overcomes the problems confronting the prior art through the novel placement of narrow layers of adhesive material which functions to attach the envelope directly to a container, while at the same time sealing an insert within the envelope.